Are you implying that the more species in existance the better? If so why?

Do you want to live in a world without any other living things? How many living things do you want? Is life less interesting if there are only two types of living beings?

I think that the world as we know it is valuable to us because we enjoy it, and nothing more. If we can't appreciate the beauty of life (most of us can't persist on the pure beauty of mathematics or conceptual analysis), what's the point?

I agree that biodiversity is a source of joy and education for me, and I'd add that it's also because we know something about ourselves--we know of the insatiability, the psychopathy, and the destructive nature that comes hand-in-hand with classical capitalism. Many of us see our conservation efforts as a necessary opposing force and as a way of saving ourselves from ourselves.

Only two creatures isn't really possible. It isn't even an ecosystem, it's a Game of Life simulation.

Yes, this sounds a lot like a Mars colony.

And you think that would be a fulfilling life if it wasn't exploring a new planet and shaping it to the way we want?

In terms of exploring a new planet, by the time people land on mars, the area they land on would have been explored by spacecraft and rovers in high detail.

In terms of shaping a planet the way we want, we can do that on earth, and more so if we figured out how to live without being dependent on other earth organisms.

You didn't answer the question. Is that life fulfilling? And is it so for most / all of the population?